Power bank



1.1 is a top, front, right perspective view of a power bank, showing our new design;

1.2 is a bottom, rear and left perspective view thereof;

1.3 is a front elevation view thereof;

1.4 is a rear elevation view thereof;

1.5 is a left elevation view thereof;

1.6 is a right elevation view thereof;

1.7 is a top plan view thereof;

1.8 is a bottom plan view thereof; and,

1.9 is a third perspective view thereof.

The broken lines are included to show features that form no part of the claimed design. 

CLAIM The ornamental design for power bank, as shown and described. 